I am a junior high Science teacher. For the
past two years I have tried to help my students
build cloud chambers. We use small plastic dishes
with black felt on the bottom and a black paper
ring around the inside edge. We use Coleman lantern
mantles and 91% isopropyl alcohol. We place this in
a Wendy's salad container along with vermiculite
and dry ice. And we wait, and wait. The room is
darkened. The children use flashlights to see into
the chamber. And they see nothing. I know I have
seen this experiment work. It has worked for
me in the past...but not these last two years.
What am I doing wrong? Does anyone have any
suggestions? Help! I would really like to do this-
but with success.
Have you tried it with a radioactive source? It is a difficult
construction; I know, I have tried it. Usually you have to compress and
expand the chamber, and you see tracks only on the expansion. But it
the expansion is not "smooth" then the cloud is turbulent and will not hold
tracks. Please let me know if you get one working.
Jack L. Uretsky
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Update: June 2012